Caption: Human head and neck, CT scan. Coloured three- dimensional computed tomography (CT) scan of an adult's head and neck. The scan reveals the bones, muscles and arteries. This image was produced using a multi-slice CT scanner, which uses a thin X-ray beam to scan around the patient collecting data from different angles to create 'slices' of the body. A computer reconstructs the slices into coloured three- dimensional images of the body, including bones and soft tissue. A contrast agent injected into the bloodstream allows blood vessels to be detected. This image was created using OsiriX medical imaging software which allows surgeons to navigate around the body using fly-through animations of the data.